BIO-112 EXAM 02/03/2023 Packet 1

Dr. Emanuelle Charpentier

Dr. Emanuelle Charpentier

• Funding and acting director of the Max Planck Unit at Humboldt University in Berlin, Germany

• Microbiologist & Geneticist

• Worked with Dr. Jennifer Doudna to decode CRISPR/CAS9 System in bacteria

• 2020 Nobel Prize in Chemistry

Scientific theories are…

an explanation for a general class of phenomena supported by a wide body of evidence.

The three theories that are the framework for biology are:

1. the theory of evolution by natural selection

2. cell theory

3. chromosome theory of inheritance

Life is…

cellular.

Robert Hooke:

1665→ created the first microscope (30x magnification)

Anton Von Leeuwenhoek:

around 1665→ developed a microscope with 300x magnification and observed the first single-celled organism

What is a cell?

• a highly organized compartment

• separated from their environment by membrane barrier

The cell theory states…

all organisms are made up of cells and all cells come from pre-existing cells.

Theodore Schwann→

→ Animals are made of cells

Matthias Jakob Schleiden→

→ Plants are made of cells

Rudolf Virchow* (might have plagiarized R. Remak)→

→ Cells come from pre-existing cells

Spontaneous generation proposed that…

organism arise spontaneously.

Louis Pasteur (1822-1895)…

put the spontaneous generation vs. cell theory concepts to the test in the 1800’s.

Pasteur’s results supported…

the cell theory because through his experiment, we know that cells do not spontaneously arise (straight-necked flask and swan-necked flask experiment)

Carbon (C), Hydrogen (H), Nitrogen (N), Oxygen (O), Phosphorous (P), and Sulfur (S) make up ___% of living cells.

99%

Covalent bonds…

share electrons.

The most electronegative molecule is…

oxygen (O).

In non-polar covalent bonds…

electrons are shared equally.

In polar covalent bonds…

electrons are not shared equally.

Solution

A solute dissolved in a solvent

The best solvent is…

Water.

Properties of water:

• excellent solvent

• small size, bent shape, highly polar

• hydrogen bonds (which are cohesive)

• density (can change from a solid to a liquid and to a gas)

• high specific heat

Hydrophobic

“water fearing” (non-polar)

Hydrophilic

“water loving” (ions, polar molecules)

Biological significance of pH:

• water breaks down into H+ and OH-

• acids give up H+ and increases protons in solution

• bases acquire H+ and decreases protons in solution

• pH effects biological function

pH (“power of hydrogen”)…

• logarithmic

• one unit of pH represents change in H+ equal to a factor of 10

Energy

the capacity to do work or supply heat

Potential energy

stored energy (related to electron positioning)

Kinetic energy

motion (thermal)

First Law of Thermodynamics

energy is conserved and cannot be created or destroyed. it can be transferred or transformed.

Entropy

the amount of disorder in a molecule.

Reactions are…

spontaneous if they proceed on their own and no energy is needed.

Processes proceed in the direction that results in…

potential energy of products less than reactants.

Thermodynamics drive…

biological processes.

Life is…

carbon (C) based.

Carbon (C) is found in…

nearly all molecules in organisms.

Organic compounds contain carbon

• limitless variety of shapes

• different combination of single and double electron bonds

Carbon (C) provides a…

“molecular skeleton”

Polymerization

small molecules (monomers) can join together into bigger molecules (polymers) via polymerization.

Monomers polymerize via…

condensation reactions.

• reverse reaction is called hydrolysis (water in, monomer out)

Macromolecules of life form via…

polymerization.

Proteins are…

the most abundant and versatile macromolecules.

Amino acids are…

the building blocks of proteins.

What happens to amino acids in water?

they ionize.

How many amino acids are there with unique side chains?

20

Side chains

• may contain functional groups

• affect solubility

Proteins are formed by…

peptide bonds.

Nucleic acids

• store the info of life

• polymer of nucleotide monomers

• nucleotides consists of a sugar, phosphate group, and a nitrogenous base

Ribonucleotides are…

monomers of RNA.

Deoxyribonucleotides are…

monomers of DNA

DNA

A→T

C→G

RNA

A→U

C→G

Carbohydrates are important in…

cell structure, identity, and energy storage.

Carbohydrates are composed of…

sugar

• monosaccarides → 1 sugar

• differ in arrangement and number of carbons

Polysaccharides are…

polymers of monosaccharides

• condensation reaction between hydroxyl (glycosidic linkage)

• energy storage: starch (plants) & glycogen (animals)

• Structural: cellulose (plants), chitin (fungi, insects, and crustaceans), & peptidoglycan (bacteria)

Lipids are…

hydrophilic, e- containing compounds

• contain hydrocarbons

Hydrocarbons are…

Non-polar molecules with only carbon and hydrogen

• saturated=only single bonds

• unsaturated=1+ double bonds (kinks)

• Building blocks of the plasma membrane

The major group of lipids are…

• steroids

• fats

• phospholipids

Steroids

bulky, four ring structure

• cholesterol, estrogen

Fats

3 fatty acids linked to glycerol

• energy storage

Phospholipids

glycerol linked to phosphate and two hydrocarbon chains

Phospholipid bilayer

• amphipathic

• hydrophobic interactions

• form spontaneously

• more stable in a cluster

• plasma membrane = life's defining barrier

Selective permeability

• small, non-charged, move easily

• large, charged cross slowly, if at all

• Other factors: length of tail (short > long), saturation stage (unsaturated>saturated), presence of cholesterol decreases permeability, temperature (slow=cold, fast=warm)